Chapter 15, Problem 7Q

Summary Introduction

To review:

The reactions involved in the process where the products of pyrimidine base catabolism are degraded to succinyl CoA (coenzyme A) and acetyl CoA.

Introduction:

The degradation of pyrimidine bases includes the conversion of uracil and thymine to β-alanine and β-aminoisobutyrate, respectively. These two conversion pathways run parallel to each other. The first step involves the reduction of uracil and thymine by dihydropyrimidine dehydrogenase. The products are hydrolyzedand the open rings of β-ureidopropionate and β-ureidoisobutyrate are formed. These molecules further degrade to form succinyl CoA and acetyl CoA.